Damper for washing machine

ABSTRACT

Disclosed is a damper for a washing machine including a cylinder, a rod of which one end is inserted in the cylinder, a sliding rod integrally formed on a proximal end of the rod, a damping part disposed around the sliding rod to perform a damping operation, the damping part having a coupling part contracting/expanding in a radial direction, a seating portion formed on the sliding rode, the coupling part being selectively located on the seating portion, and a magnet formed on the coupling part.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a damper for a washing machine, and more particularly, to a damper that is designed to exert multiple stages of damping force in response to an amount of vibration generated in the washing machine to properly attenuate the vibration, small and large, thereby stably operating the washing machine under a low noise state. Further, the present invention is directed to a multiple-stage damper for a washing machine, which is designed such that damping force can be positively controlled by a predetermined control system, thereby more effectively attenuating vibrations generated in an excessive vibration section and a steady vibration section.

[0003] 2. Description of the Related Art

[0004] Generally, washing machines are classified according to the washing method into a drum type, an agitator type, and a pulsator type. Particularly, the drum type washing machine has a rotational drum provided at an inner wall with a protruded member, being designed to perform washing using physical impact generated when the laundry ascended by the protruded portion along an inner circumference of the drum drops.

[0005] In recent years, such a drum type washing machine has been widely used as a household washing machine as it has advantages of reducing the damage of the laundry and saving water.

[0006] The pulsator type washing machine includes an upright drum having an opened top and a pulsator installed on an inner bottom of the drum. The pulsator type washing machine is designed to perform washing using rotational force of the pulsator or the drum. The agitator type washing machine includes an upright drum having an opened top and an agitator installed in the drum, thereby performing washing using forced water flow generated by the rotation of the agitator.

[0007] The washing machine may be further classified according to a variety of method. For example, it can be classified according to a laundry loading method into a front-loading type where the laundry is loaded through the front, a top-loading type where the laundry is loaded through the top, and a side-loading type where the laundry is loaded through the side.

[0008] Regardless of the washing method and the laundry loading method, all of the washing machines have a motor and a movable part rotated by the motor. When the movable part is rotated by the motor, vibration is generated in the washing machine, causing the noise and the abnormal operation of the washing machine. For example, the vibration may cause a variety of problems such as a walking phenomenon where an installed location of the washing machine is displaced and an RPM reduction of the movable part by friction between the movable part and a stationary part. Therefore, the washing machine manufactures have aspired to develop a method and system that can attenuate the vibration generated when the washing machine is operated. The conventional washing machine has employed a one-stage damper having a fixed damping constant to attenuate the vibration. That is, regardless of the operation state of the washing machine, a fixed damping constant is applied to the movable part. However, since the vibration generated in the movable part is varied at every stroke of the washing machine, it is not preferable that the fixed damping constant is applied to the movable part.

[0009] That is, the operation of the washing machine is done going through a small vibration section and a large vibration section. For example, in a variable RPM section such as an initial stage of a spinning cycle (a dehydrating cycle) where the RPM of the movable part is varied, relatively large vibration is generated. In a steady RPM section where the RPM of the movable part is not varied, relatively small vibration is generated.

[0010] To solve the above problem, a two-stage damper that can attenuate the vibration in response to a physical amount of vibration has been proposed. However, since such a two-stage damper performs the damping operation according to an amount of one-dimensional vibration, there is a problem that the vibration cannot be properly attenuated.

[0011] In addition, while the amount of vibration is linearly varied, the damping constant of the damper is not linearly varied. That is, since the damping constant of the damper is varied by a predetermined step, the vibration variably generated in the movable part cannot be quickly attenuated. Furthermore, since a method for positively controlling the damping constant of the damper has not been proposed, there is a problem that it is difficult to generally control the washing machine.

SUMMARY OF THE INVENTION

[0012] Accordingly, the present invention is directed to a damper for a washing machine that substantially obviates one or more problems due to limitations and disadvantages of the related art.

[0013] An object of the present invention is to provide a damper for a washing machine, which can provide a stable operation to the washing machine by positively controlling the operation state of the washing machine.

[0014] Another object of the present invention is to provide a damper for a washing machine, which can positively alleviate vibration generated in the washing machine in accordance with a mode preset by a user.

[0015] Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

[0016] To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided a damper for a washing machine, comprising: a cylinder; a rod of which one end is inserted in the cylinder; a sliding rod integrally formed on a proximal end of the rod; a damping part disposed around the sliding rod to perform a damping operation, the damping part comprising a coupling part contracting/expanding in a radial direction; a seating portion formed on the sliding rode, the coupling part being selectively located on the seating portion; and a magnet formed on the coupling part.

[0017] In an aspect of the present invention, there is provided a damper for a washing machine, comprising: a cylinder; a rod of which one end is inserted in the cylinder; a sliding rod integrally formed on a proximal end of the rod; a hollow external part having a relatively large inner diameter; a coupling part defined by a magnet inserted in the hollow external part, the coupling part being coupled on the sliding rod when magnetic force is formed; and a damping pad formed on an outer circumference of the hollow external part, the damping pad frictionally contacting an inner circumference to perform a damping operation.

[0018] In another aspect of the present invention, there is provided a damper for a washing machine, comprising: a cylinder; a rod of which one end is inserted in the cylinder; a sliding rod integrally formed on a proximal end of the rod; an electromagnet inserted in the sliding rod; and a damping part disposed on an outer circumference of the sliding rod, the damping part being fixed on the sliding rode when the electromagnet is magnetized.

[0019] In a further aspect of the present invention, there is provided a damper for a washing machine, comprising: a cylinder; a rod of which one end is inserted in the cylinder; a damping part contacting the cylinder to perform a damping operation; and a coupling part formed in the cylinder to be selectively fixed on the rod.

[0020] By the damper of the present invention, the washing machine is operated with a low noise. In addition, the damper is not easily damaged even when strong vibration of the movable part is transmitted from the movable part.

[0021] By the damping operation of the damper as proposed above, the vibration generated in the washing machine can be quickly attenuated with a low noise.

[0022] In addition, the damage of the damper that may be caused by transiently strong vibration can be prevented.

[0023] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:

[0025]FIG. 1 is a perspective view of a drum type washing machine where a damper according to a first embodiment of the present invention is employed;

[0026]FIG. 2 is a sectional view of the damper according to a first embodiment of the present invention;

[0027]FIG. 3 is a sectional view taken along the line A-A′ of FIG. 2;

[0028]FIG. 4 is a sectional view of a damper according to a first embodiment, illustrating a damping operation for attenuating excessive vibration when a washing machine is in an initial dewatering operation;

[0029]FIG. 5 is a sectional view of a damper according to a first embodiment, illustrating a damping operation for attenuating relatively small vibration of a drum when a washing machine is in a steady dewatering operation;

[0030]FIG. 6 is a sectional view of a damper according to a second embodiment of the present invention;

[0031]FIG. 7 is a sectional view taken along the line B-B′ of FIG. 6;

[0032]FIG. 8 is a sectional view of a damper according to a second embodiment, illustrating a damping operation for attenuating excessive vibration of a drum when a washing machine is in an initial spinning operation; and

[0033]FIG. 9 is a sectional view of a damper according to a second embodiment, illustrating a damping operation for attenuating relatively small vibration of a drum when a washing machine is in a steady spinning operation.

DETAILED DESCRIPTION OF THE INVENTION

[0034] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0035] In the embodiments of the present invention, a drum type washing machine is exemplified. However, the present invention is not limited to the drum type washing machine. The present invention can be applied to a variety of devices generating vibration as well as other types of the washing machine.

[0036] First Embodiment

[0037]FIG. 1 shows a perspective view of a drum type washing machine where a damper according to a first embodiment of the present invention is employed.

[0038] As shown in the drawing, a drum type washing machine comprises a case 3, a tub 1 disposed in the case 3 to store water, a drum 2 disposed in the tub 1 to receive the laundry, and a driving motor 10 disposed on a rear side of the tub 1 to rotate the drum 2.

[0039] The operation of the drum type washing machine will be described hereinafter.

[0040] Rotational force of the driving motor 10 is transmitted to the drum 2 via a belt 11. When the drum 2 rotates, the laundry loaded in the drum 2 rotates together with the drum 2. At this point, since the drum 2 rotates with a relatively low RPM, the laundry ascends by the rotation of the drum 2 and drops by a gravity to collide with the water contained in the tub 1. By colliding force between the laundry and the water, dirts and contaminants stuck on the laundry are removed. Although the driving force of the driving motor 10 is transmitted to the drum 2 via the belt 11 in this embodiment, the driving motor 10 may be designed to directly rotate the drum 2. Even when the driving motor is directly connected to the drum 2, it will be apparent that the vibration is generated by the rotation of the drum 2.

[0041] In addition, the washing machine further includes a weight 4 disposed on an outer circumference of the tub 1 to correct the center of gravity in a multi-direction, a spring 5 having opposite ends respectively connected to the case 3 and the tub 1 to alleviate vibration generated from both the tub 1 and the case 3, and a damper 8 having opposite ends respectively connected to the case 3 and the tub 1 to attenuate vibration generated in the tub 1.

[0042] The weight 4 is designed to correct the center of gravity of the tub 1 to radically alleviate the vibration that may be generated by the eccentric center of gravity of the tub 1.

[0043] The vibration generated by the operation of the tub 1 is first absorbed by the spring 5 and is then attenuated by the damper 8. As a result, the vibration generated in the course of the operation of the tub 1 can be quickly removed.

[0044] In detail, the damper includes a cylinder 161 of which one end is fixed to the tub 1, and a rod 162 of which one end is fixed to the case 3 and inserted into the cylinder 161. Of course, the damper 8 may be constructed such that the rod 162 is connected to the tub 1 and the cylinder is connected to the case 3.

[0045] Describing operation of the damper 8, a damping pad is inserted between the rod 162 and the cylinder 161 inserted into the rod 162, and is in contact with an inner circumference of the cylinder 161. When vibration generated from the tub 1 is transferred to the cylinder 161 so that the cylinder 161 and the rod 162 are displaced different with each other in the length direction, damping is performed by a frictional force between the inner circumference of the cylinder 161 and the damping pad (see numeral 170 of FIG. 2).

[0046] Shape and structure of the damper will be described hereinafter.

[0047]FIG. 2 shows a damper according to a first embodiment of the present invention and FIG. 3 shows a sectional view taken along the line A-A′ of FIG. 2.

[0048] As shown in the drawings, the damper 8 includes a hollow cylinder 161, a rod 162 of which one end is inserted in the cylinder 161, a sliding rod 163 integrally formed on an end of the rod 163, an electromagnet 166 disposed in the sliding rod 163, a coil 167 wound around the electromagnet 166, and a damping part 168 slidably disposed on an outer circumference of the sliding rod 163 to selectively fixed on the sliding rod 163 when the electromagnet 166 generates magnetic force.

[0049] Provided on opposite sides of the damping part 168 are springs 173 for supporting the damping part 168 and the sliding rod 163 with respect to each other.

[0050] That is, the damping part 168 includes an external part 169 having a relatively large inner diameter and a coupling part 170 inserted in the external part 169 and contracted and fitted in the sliding rode 163 when the electromagnet 166 is magnetized, and a damping pad 172 formed on an outer circumference of the external part 169 to exert damping force by frictional action with the inner circumference of the cylinder 161. The coupling part 170 is comprised of two sections each formed in a semicircular shape having a convex top and a concave bottom. The coupling part 170 is formed of a magnetic material such as iron that can react to the electromagnet 166.

[0051] When the electromagnet 166 is magnetized, the coupling part 170 is contracted in a radial direction. Particularly, in order for the coupling part 170 to expand in a radial direction when the electromagnet 166 is degaussed, the sections of the coupling part 170 are connected to each other by elastic members 171. The elastic member 171 may be formed of a spring or synthetic resin.

[0052] In order for the electromagnet 166 to be inserted in the sliding rode 163, the sliding rod 163 is provided with an electromagnet insertion portion 164. The electromagnet insertion portion 164 is provided at top and bottom with seating portions 165 that allow the coupling part 170 to be inserted in the sliding rod 163 when the coupling part 170 is displaced by the magnetic force of the electromagnet 166. That is, the seating portions 165 are formed corresponding to the sections of the coupling part 170 so that the coupling part 170 can be in surface-contact therewith when the coupling part 170 contracted by the magnetic force of the electromagnet 166 is located thereon.

[0053] The operation of the above-described damper will be described hereinafter.

[0054]FIG. 4 illustrates a damping operation for attenuating excessive vibration of the drum when the washing machine is in the initial dewatering operation, while FIG. 5 illustrates a damping operation for attenuating relatively small vibration of a drum when a washing machine is in a steady dewatering operation.

[0055] Referring first to FIG. 4, the damper 8 is designed to generate high frictional damping force in the initial dewatering operation where the excessive vibration is generated. That is, after the electric power is applied to the electromagnet 166 inserted in the sliding rode 163, the drum 2 spins to remove water from the laundry. In the initial dewatering operation, the excessive vibration is generated on the drum 2. The generated vibration is applied to the damper 8 and thereby the rod 162 and the cylinder 161 differently move relative to each other in a horizontal direction. At this point, the sliding rod 163 can move by a distance identical to that the rod 162 moves in a state where it is integrated with the rod 162.

[0056] In addition, the rod 162 applies moving force to the damping part 168 via the spring 173. When the damping part 168 moves by the moving force to be aligned with the electromagnet 166 in a vertical direction, the coupling part 170 moves toward the electromagnet 166 by the magnetic force of the electromagnet 166 such that the coupling part 170 is fitted on the seating potion 165. At this point, opposite ends of the coupling part 170 is located in the damping part 168.

[0057] As a result, the sliding rod 163 and the damping part 168 moves in a state where they are integrated as a single body with the coupling part 170 interposed between them.

[0058] In this state, when the rod 162 linearly move relative to the cylinder 161, damping is performed by frictional force between the damping pad 172 and the inner circumference of the cylinder 161. That is, the excessive vibration generated in the washing machine can be sufficiently alleviated by the damping force generating on the contact surface between the damping pad 172 and the cylinder 161. The arrow in the drawing represents the relative motion of the damping pad 172 to the cylinder 161.

[0059] Referring to FIG. 5, in the steady dewatering operation where the drum 2 stably spins, relatively small vibration is generated on the drum 2 and thereby frictional force between the inner circumference of the cylinder 161 and the damping pad 172 may be reduced. Therefore, the electric power being applied to the electromagnet 166 is cut off to degauss the electromagnet 166. As a result, the radial diameter of the coupling part 170 is increased by elastic force of the elastic members 171. The coupling part 170 is removed from the seating portion 165 so that the sliding rod 163 and the damping part 168 can be free from each other.

[0060] As a result, by the repeated compressing/expanding operation of the springs 173 disposed on the opposite sides of the damping part 168 as well as the frictional force generated between other elements, the damping is realized. That is, the vibration of the washing machine is attenuated by the relatively small damping force of the damper 8. The arrow in the drawing indicates the motions of the sliding rod 163 and the spring 173.

[0061] Second Embodiment

[0062]FIGS. 6 and 7 illustrate a second embodiment of the present invention. That is, FIG. 6 shows a sectional view of a damper according to the second embodiment of the present invention and FIG. 7 shows a sectional view taken along the line B-B′ of FIG. 7.

[0063] A damper 8 of this embodiment is configured to include a hollow cylinder 261, a rod 262 of which one end is inserted in the cylinder 261, a sliding rod 263 integrally formed on an end of the rod 262, a hollow external part 269 having a relatively large inner diameter, an electromagnet 275 inserted in the external part 269, a coupling part 270 inserted in the sliding rod 263 while being contracted when magnetic force is exerted, and a damping pad 272 disposed on an outer circumference of the external part 269 to exert damping force while generating frictional force with the inner circumference of the cylinder 261. The external part 269, the coupling part 270 and the damping pad 272 can be called as a damping part 268. The electromagnet 275 is defined by the coupling part 270 and a coil 276 wound around a side or opposite sides of an outer circumference of the coupling part 270. At this point, the sliding rod 263 is provided with a seating portion 264 where the coupling part 270 is located.

[0064] This second embodiment is identical to the first embodiment except for the structure of the electromagnet. That is a feature of the present invention is that the displacement of the coupling part 270 is realized by the electromagnet defined by the coil 276 wound around a core defined by the coupling part 270.

[0065] The operation of the second embodiment will be described hereinafter.

[0066]FIG. 8 shows a sectional view of a damper according to a second embodiment, illustrating a damping operation for attenuating excessive vibration of a washing machine an initial dewatering operation, while FIG. Shows a sectional view of a damper according to a second embodiment, illustrating a damping operation for attenuating relatively small vibration of a washing machine in a steady dewatering operation.

[0067] Referring first to FIG. 8, in the initial dewatering operation where the excessive vibration is generated, electric power is applied so that the coupling part 270 is contracted as sections of the coupling part 270 are attracted to each other by magnetic force and fitted in the seating portion 264 of the sliding rod 263. Accordingly, the sliding rod 263 moves together with the damping pad 272 and the damping operation is realized by frictional force generated between the damping pad 272 and the inner circumference of the cylinder 261. The detailed operation is identical to that in the first embodiment.

[0068] Referring to FIG. 9, in the steady dewatering operation where relatively small vibration is generated, the external electric power is cut off to remove the magnetic force. As a result, the coupling part 270 is expanded in a radial direction by the biasing force of the elastic members 271 to move away from the seating portion 264, whereby the sliding rod 263 and the damping part 268 are designed to move relative to each other.

[0069] As a result, the damping force is exerted by the repeated compressing/expanding operation of the springs 273 supporting the damping part 268 and by frictional force generated between other elements.

[0070] As described above, the damper of the present invention can positively alleviate the excessive vibration generated in the initial dewatering operation as well as the relatively small vibration generated in the steady dewatering operation in accordance with a control condition preset by the present invention, thereby realizing the low vibration/low noise washing machine.

[0071] Particularly, since the damping force is positively varied in response to the operation state of the washing machine, the noise and vibration of the washing machine can be further reduced.

[0072] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. 

What is claimed is:
 1. A damper for a washing machine, comprising: a cylinder; a rod of which one end is inserted in the cylinder; a sliding rod integrally formed on a proximal end of the rod; a damping part disposed around the sliding rod to perform a damping operation, the damping part comprising a coupling part contracting/expanding in a radial direction; a seating portion formed on the sliding rode, the coupling part being selectively located on the seating portion; and a magnet formed on the coupling part.
 2. The damper according to claim 1, further comprising first and second springs respectively disposed on both sides of the damping part.
 3. The damper according to claim 1, wherein the damping part further comprises: a hollow external part in which the coupling part is disposed; and a damping pad formed on an outer circumference of the hollow external part, the damping pad contacting the cylinder to create frictional force.
 4. The damper according to claim 1, wherein the coupling part is formed in a semicircular shape.
 5. The damper according to claim 1, wherein the coupling part comprises two sections disposed to be symmetrical to each other, the two sections being connected by an elastic member.
 6. The damper according to claim 1, wherein the magnet is formed on an inside of the seating portion.
 7. The damper according to claim 1, wherein the magnet is an electromagnet.
 8. The damper of claim 1, wherein the magnet comprises a coil wound around the coupling part functioning as a core.
 9. The damper according to claim 1, wherein the rod is integrally formed with the sliding rod.
 10. A damper for a washing machine, comprising: a cylinder; a rod of which one end is inserted in the cylinder; a sliding rod integrally formed on a proximal end of the rod; a hollow external part having a relatively large inner diameter; a coupling part defined by a magnet inserted in the hollow external part, the coupling part being coupled on the sliding rod when magnetic force is formed; and a damping pad formed on an outer circumference of the hollow external part, the damping pad frictionally contacting an inner circumference to perform a damping operation.
 11. The damper according to claim 10, wherein the coupling part is selectively inserted in a groove formed on the sliding rod.
 12. The damper according to claim 10, wherein the coupling part comprises two sections that are symmetrically disposed.
 13. The damper according to claim 10, wherein the magnet is an electromagnet that is magnetized by an external electric force.
 14. A damper for a washing machine, comprising: a cylinder; a rod of which one end is inserted in the cylinder; a sliding rod integrally formed on a proximal end of the rod; an electromagnet inserted in the sliding rod; and a damping part disposed on an outer circumference of the sliding rod, the damping part being fixed on the sliding rode when the electromagnet is magnetized.
 15. The damper according to claim 14, further comprising a damping pad formed on an outer circumference of the damping part, the damping pad contacting an outer circumference of the cylinder.
 16. The damper according to claim 14, wherein a diameter of the sliding rod is smaller than a diameter of the rod.
 17. The damper according to claim 14, further comprising a spring formed on at least one side of the damping part to support the damping part.
 18. A damper for a washing machine, comprising: a cylinder; a rod of which one end is inserted in the cylinder; a damping part contacting the cylinder to perform a damping operation; and a coupling part formed in the cylinder to be selectively fixed on the rod.
 19. The damper according to claim 18, further comprising a damping pad formed on an outer circumference of the damping part.
 20. The damper according to claim 18, wherein the coupling part is formed of a magnetic material to move by magnetic force of the magnet.
 21. The damper according to claim 18, wherein the coupling part comprises a plurality of sections, at least one of which is an electromagnet.
 22. The damper according to claim 18, wherein the coupling part is formed of a magnetic material, comprising a magnet disposed on a predetermined location of the rod. 